Orbiting Lasers for Hydrogen Power 402
DerekLyons writes: "Yahoo is carrying a story about a Japanese scientist who plans to use giant orbiting lasers to extract H2 from seawater. The interesting part of the scheme is that design uses solar pumped lasers, which avoid the loss of efficiency (and increased launch weight) from powering the laser with electricity from solar cells. Is the way to finally break the main dilemma of the hydrogen economy? (That it takes more energy to make the hydrogen than you gain in using it.)"
Thermodynamics (Score:4, Informative)
Look, due to the laws of thermodynamics it will ALWAYS take more energy to obtain a resource than to use it. Same applies for oil - once we're out of it, it will be very damn expensive to "make" it. So a lot of these arguments against renewable energy sources are just rubbish. Sure, you don't get as big of an *immediate* payoff, but you get a much steadier, reliable payoff over time. The trick is amortizing the expense of using a certain fuel by using the byproducts in a very efficient way. We waste such vast amounts of energy both in direct use, and in unrecaptured efficiency, that I'm sure any number of energy sources will be totally viable (hydrogen, wind, solar, thermal, hydro, methane). But of course many of these will require social changes that nobody is willing to make. To paraphrase Denis Leary, everybody wants to get themselves a 1967 Cadillac El Dorado convertible, hot pink with whaleskin hub caps and all leather cow interior and big brown baby seal eyes for headlights, drive around in that baby at 115mph getting one mile per gallon, sucking down quarter pounder cheese burgers from McDonald's in the old-fashioned non-biodegradable styrofoam containers and when they're done sucking down those grease ball burgers, wipe their mouths with the American flag and toss the styrofoam container right out the side and there ain't a God damned thing anybody can do about it.
Enviromental effects ???? (Score:4, Informative)
My understanding is it REQUIES VERY HIGH temperatures to Dissacociate water on the order of 3500 degreesf plus (PS Dont ever try to quelch a thermite reaction with water
Ok so were using Ti02 as a catalyst, what my question is what about thermal evnviormental pollution, hell in some cases its worse than chemical pollution. Hmm were encountering a greenhouse effect globally lets fire oh say 50 or so 10+ megawat lasers at earth. (Its only one until it works)
If this is going to be succesfull youll see a commercial proliferation of these without regard for saftey, No dont think so , look at the oil companies and their rigs , then consider again when Oil companies see this as the next big thing ?
Hell with all that free hydrogen you could manufacture your own hydrocarbons CHEAP, aka GAS
Nice big vicious cycle Gotta Love Science
Re:Solar cell (Score:2, Informative)
Using it to boil water for a steam engine might work. Or just powertrip and kill everyone else using the energy of the world and then you don't have to worry about conservation anymore
Re:Replies (Score:5, Informative)
I predict that within 30 minutes, there will be at least two confused posts saying that we should just use solar panels to generate electricity to "crack" the hydrogen from sea water.
...except that, instead of using electrical conversion followed by electrolysis they will use photocatalysis, as described in this Physics World Article [physicsweb.org], which talks about the implications of a paper published in Nature.
The jist of it, for the link weary, is that by the use of a cunning contrived semiconductor it is possible to arrange the band-gap to be higher that the reduction potential of H2, which allows the production of H2 from the H+ ions that are always present in water.
Early days yet (efficiency is 0.66%, compared with an break-even of 4%), and lifetimes are unknown at the moment. But using solar panels to generate hydrogen should not be rejected out of hand just because the energetics are unfavourable with one particular type of solar cell.
Micheal, dear Micheal... (Score:1, Informative)
Re:Enviromental effects ???? (Score:2, Informative)
Hold on to your horses, Fermi.
High temperatures do not dissociate molecules; high amounts of energy do (there's a big difference). A laser, being a concentrated energetic source, could provide that much energy. By the way, you can't quench thermite with water simply because it's too hot and the water will vaporize before quenching anything.
TiO2 (not "tee-eye-zero-two") is a common catalyst. Catalysts, by definition, are retrieved after the reaction and not consumed. There should be little pollution from the use of this material.
I'm not sure about thermal pollution, but I believe that because air is mostly nothing (there's only a few atoms in a relatively large volume of air), there shouldn't be much increase in the temperature of the air (or deflection of the laser). Once it hits the water on the floating island, the desired reaction should take place. I think most of the energy in the laser would be used to break the water molecules and little would go to the surroundings.
Free hydrogen will not get you cheap hydrocarbons. You'd have to use more energy to do this (although you could easily hydrogenate more of those lovely animal fats in your diet).
Nice big cycle; you do hafta love science.
Re:What about a flock of birds (Score:1, Informative)
Anyone know of a megawatt class solid state light pumped laser ? Too much of the energy pumped in to heats the laser material. You get thermal distortions (it melts). Someone else already pointed out that you need specific wave lengths of light for yout pump.
BTW. What happens if you fly an aircraft through one of these laser beams ?
Re:Why Not Fission? (Score:2, Informative)
Re:main dilemma? (Score:1, Informative)
It's only a matter of scaling. Prototypes are always more expensive that mass produced product.
http://www.nmsea.org/Curriculum/Primer/from_oil
(about half way down the page)
http://www.sandia.gov/Renewable_Energy/solarthe
If we began a "Manhatten Project" for Solar II we could be energy independent within a decade. As it is, the teenagers alive today will consume ALL of earth's fossile reserves in their lifetime. And, even if we could find 10X more coal and oil than is presently known, or increase the efficiency of our use of fossile fuels by 90%, the gains would only postpone the end by 10-20 years. Given Joe Sixpack's ledgendary stupidity and short sightedness our politicians have no need to worry about the future till it gets here. Unfortunately, by then it will be too late.
Re:hydrogen economy issues (Score:5, Informative)
Sorry, but you managed to be substantially wrong in parts of BOTH of your points :-)
not to mention the industry mogul's vested interest
You keep hearing this ridiculous statement from people, and I don't understand how people think a future hydrogen economy would be any different. If and when we move to a hydrogen based energy economy, who do you think will be the ones extracting, storing, shipping, and selling the hydrogen? I'll give you one guess... the current players that dominate the petroleum/coal based energy economy. They're the ones that have the capital to make it happen.
Incidentally, the energy industry would LOVE to be able to natively produce hydrogen, and be paid for creation, distribution, and sale; they would drop oil in a heartbeat if they could, because there would be more profit at a lower cost, and that is always a win. There is VASTLY more uncertainty in doing business in the parts of the world that have the most oil than it is to do business in the first world, and that drives up costs tremendously. There are huge expenses in extraction, transportation, storage, refinement, bribes, legal issues, and taxation that just would not be encountered if they could do all of these things at home. And let's not forget that they would score a big PR win for their support of the "environment" (no more "pollution", no more spills, no more ground water contamination, etc...). There is no upside to "protecting" oil once the technology is there to produce/store/transport hydrogen cheaply.
there are always energy costs to creating portable forms of energy, but that's the issue, not that it's more energy-expensive to create hydrogen than to use it.
No, that really isn't the point. The point the previous poster was trying to make is that the energy cost of extracting, processing, shipping, and selling petroleum based products is substantially LOWER than the amount of energy extracted from the oil. This is because the energy has already been stored for us, for free, in the oil; burning the oil releases the stored energy, and digging it up costs almost nothing energy-wise. For hydrogen, however, there is no such "free store" we can dig up. Combine hydrogen with oxygen to get water, and you get a relatively huge release of energy, but we have no previously STORED source of hydrogen; we have to disassemble water to get that hydrogen. But, the energy cost of cracking water is substantially HIGHER than the amount of energy that can later be extracted from the stored hydrogen. So, there is currently no feasible way to phase out our use of petroleum; in fact, if we switched to hydrogen power in our cars today, it would drive UP the demand for oil, not decrease it (a similar problem would occur if we all went out and switched to electric cars today). The real benefit of oil is not its portability; the real benefit is that it stores vastly more chemical energy than it takes to extract it from the ground.
Re:Hydrogen is mediocre as a fuel (Score:2, Informative)
Cat
Re:Offtopic - Weapons in Space (Score:2, Informative)
The majority of the United States, however, thinks everything beyond the border (any border!) is some big territorial mass called "Mexico" whose population will speak perfect if slightly accented English when pressed with slower, louder sentences by the tourists, just like in the movies.
Sometimes, someone belonging to that majority will be elected for some public office, and that along with the pressure from the voters who think Asia is part of the Middle East will invalidate any foreign policy not based on total obliviousness to the external world.
Re:Thermodynamics (Score:3, Informative)
>
>An interesting observation, but I think that it is possible that the reason that this works in Civ or MOO (though I have played neither) is that, in that defined system, maximizing research delivers maximimum game-end benefit. I don't think the same is necessarily true in meatspace (ie diminishing returns from long term investment as we reach limits of what is possible). Also, there is no game end the real world.
Fair enough - but we've seen it happen in the real world, too.
ca. 5000-7000 BC: "Dawn of Civilization" - agricultural societies gradually came to dominate over their nomadic brethren, because the ability to grow more food than your people can eat allows the development of a leisure class who can invent stuff. Technologies: Agriculture, Religion, Writing.
16th-Century North America: Cavalry with muskets (4-2-1) beat foot-mounted soldiers with hand weapons (2-1-1). Kill ratios of 100:1. (Technology: Domestication of the horse, which didn't exist in North America at the time)
Poland, 1939: Mechanized infantry beat mounted cavalry. (Technology: Internal combustion engine)
Iraq, 1990: Air power (better aircraft, higher-rated pilots) and sea power (nuclear-powered aircraft carrier) cut off lines of supply long enough to wear down enemy troops, which could then be mopped up. (Technology: Air power, fission plant)
Yugoslavia, Afghanistan: Air power beat ground power hands-down. Just yesterday, I read a plausible account in the mainstream media of 10 Green Berets using force multipliers like remote sensing equipment, superior communications, and smart weapons to direct air power and achieve a 100:1 kill ratio. (Technology: Air power multiplied by semiconductors as used in communications, computer chips, CCDs and laser diodes)
The reason why Civ designers made technology a key to "winning the game" is because it's been demonstrated to work in the Real World.
A Better method...Doing it on Earth (Score:2, Informative)
Here's a more promising method for Hydrogen cracking [hionsolar.com] without adding more junk into orbit around this planet.
Go, Go, Gadget.